Amsat-UK Bulletin 01Apr98

Following press release is embargoed for automatic release at 0001/01Apr98
Satellite operators will be aware that extremely small factors can alter
things in space such as the trick with some of the earlier satellites where
the antenna elements were painted white on one side and black on the other
side; photon pressure then caused the body to spin.
G3IOR lives in East Anglia (Eastern UK) and has brought the following to
the notice of Amsat-UK. We think it deserves wider publicity, so here it is.
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Since use of the of the microsats began the East Anglian Satellite
Tracking Element Radio-amateurs (EASTER) have been concerned that the
Keplerian elements clearly show an increased 'bunching' of the cluster,
which, if allowed to continue unabated, would eventually result in one
compacted cluster forming a single satellite. This congregating has been
brought about by the fact that most users load the satellite at AOS, but
have finished doing so long before LOS.
The frontal pressure impact imparted to the approaching and leading
satellites coupled with the minimum impact to the trailing and receding
microsats (by when most users have completed their loading) has resulted in
path compaction, exacerbated by the fact that the closer the satellites
become, the greater the mutual 'G' attraction. (Whilst the leading and last
satellites have satellite attraction on one side only, the central orbiters
have both sides gravitationally attracted, so further increasing the
cluster effect).
A further worrying problem is the additional mass imparted to the
satellites imposed by those loading many megabytes over the northern
hemisphere, where the use is 11.38 times greater than the loading level
occurring when the orbiters are in the southern hemisphere. This has the
opposite effect to that of a kick motor, as it imparts non-impartial drag
by an 11.38 : 1 squared ratio which is slowly but surely increasing the
ellipticity and apogee and decreasing the perigee of the microsats.
To avoid the 'Molniya' de-orbiting effect that would eventually result
in the re-entry of the microsat cluster (as came about with OSCAR-13), the
Easter Island AMSAT Group and the Heard Island AMSAT Group (HI-AMSAT), both
being in the Southern Hemisphere, will between 2359 on March 31st and 0001
April 2nd fully load the satellites memory to maximum mass capacity in
order to counter and correct the hemispheric imbalance. To ensure that the
maximum southern loading is brought about, a minimum of loading activity is
requested of all users to the north of the equator.
To further enhance the relative distribution of the loading, G3RWL (in
the northern hemisphere) will be placing messages consisting of negative
bytes (nega-bytes) when the microsats are within his range in this same
period. Thus any messages uploaded by G3RWL will be utterly devoid of all
useful information content. Users should not attempt to download these
negative information bulletins for the simple reason of not reducing the
content imbalance required to re-assert the desired re-positioning. If
users MUST use the microsats, they also should employ nega-bytes to produce
empty messages. If they are only equipped with the more common posi-bytes,
then it is respectfully requested that they use the memories as lightly as
they can, using 'Q' Codes to reduce message loading and pressing their keys
as gently and softly as possible. Other "tips" are: not typing in large
block capitals; typing in airmail font (say 15 or 17 lpi); and using smaller
words, not more than two syllables, perferably one.
The result of the relocation experiment should be clearly seen by a
study of the next set of 'KEPS' emanating from NORAD/NASA/AMSAT. If the
corrective measures fail, meteor-scatter groups will be advised well in
advance of the forthcoming activity.
73, Pat, G3IOR @ GB7LDI
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Respectfully submitted
Richard W L Limebear G3RWL
g3rwl@amsat.org
FOC # 1188